A PCB Design Potpourri

In this column, I will be revisiting topics covered in some of my older columns and fleshing them out with new, updated information. In this job, I truly learn something every day, and I’m happy to share a few notable nuggets with you.

The Quote Process

Ultimately, whether it’s a quick-turn or standard lead-time job, customers would like to see all quotes back within a couple of hours, not a couple of days. Additionally, they want to see accurate quotes that take into account all additional processes. It’s never good when, once quoted, the fabricator comes back with additional costs for unforeseen processes. Again, this is why it is important to get a manufacturing review done if anything outside the norm is required on the drawing or quote. This includes a proper review of impedances to ensure that materials are available and the impedances work without requiring large variances in dielectric or line sizes, buy-offs for any deviations of material type or copper weights, etc.

Beyond the quote process, be sure that your fabricator is capable of all the processes necessary to ensure the board is built as expected. You want your board shop to be IPC-6012 Class 3 capable and ISO certified, and perhaps ITAR as well. Even if you can’t visit the shop for a physical qualification, send them a job to quote and see how they respond. A good fabricator will be diligent and get back to you within a few hours after completing a preliminary examination of the files, impedance calculations and proposed stackup if the board is impedance/dielectrically controlled. They should also be able to let you know right away if the job does not meet their process minimums and can’t be built. If deviations are allowed, a good fabricator will also have an alternative for many situations, such as a deviation for material type, starting copper weight, dielectrics or line sizes to be able to produce the job.

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In Part 1 of this series, Paul Taubman made the bold statement that the PCB layout is just as much a mechanical effort as it is an electrical one. In Part 2, he threads the needle, explaining why he believes that a PCB truly a mechatronic design, and why mechanical engineers may be more prepared to take on the PCB layout.

With the development of communication and IT industries and the ever-increasing demand for information analysis, many chip makers have racked their brains trying to provide customers with better technology, such as increased computing power and storage capacity of chips as well as diversifying their product offerings.

You’ll need to refer to your fab house, both to ensure that they can build what you need, and to get the final say on their design rules. Some fab houses even have downloadable design rules for various CAD packages. That makes setting things up a lot easier.

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A PCB Design Potpourri

In this column, I will be revisiting topics covered in some of my older columns and fleshing them out with new, updated information. In this job, I truly learn something every day, and I’m happy to share a few notable nuggets with you.

The Quote Process

Ultimately, whether it’s a quick-turn or standard lead-time job, customers would like to see all quotes back within a couple of hours, not a couple of days. Additionally, they want to see accurate quotes that take into account all additional processes. It’s never good when, once quoted, the fabricator comes back with additional costs for unforeseen processes. Again, this is why it is important to get a manufacturing review done if anything outside the norm is required on the drawing or quote. This includes a proper review of impedances to ensure that materials are available and the impedances work without requiring large variances in dielectric or line sizes, buy-offs for any deviations of material type or copper weights, etc.

Beyond the quote process, be sure that your fabricator is capable of all the processes necessary to ensure the board is built as expected. You want your board shop to be IPC-6012 Class 3 capable and ISO certified, and perhaps ITAR as well. Even if you can’t visit the shop for a physical qualification, send them a job to quote and see how they respond. A good fabricator will be diligent and get back to you within a few hours after completing a preliminary examination of the files, impedance calculations and proposed stackup if the board is impedance/dielectrically controlled. They should also be able to let you know right away if the job does not meet their process minimums and can’t be built. If deviations are allowed, a good fabricator will also have an alternative for many situations, such as a deviation for material type, starting copper weight, dielectrics or line sizes to be able to produce the job.